1. Field of the Invention
The present invention is directed toward a material dispensing container, and more particularly to such containers that hold solid, semi-solid, or liquid materials and allow those materials to be dispensed by the forces created on a piston by a foldable segmented band.
2. Prior Art Statement
Containers with moveable pistons have been used to dispense materials for centuries, and over the years dozens of different technologies have been developed to move such pistons. When piston containers are used to store a solid material, often a solid shaft is threaded through the piston, and the piston is moved back and forth within the container by turning the threaded shaft. However, when semi-solid or liquid materials are stored in a container, often a threaded shaft can not be used because of possible leakage and/or contamination. Thus, the integrity of the material storage volume must be maintained. In these applications, methods of moving the piston within the container were developed that would not interfere with the stored material nor cause a great deal of space within the container to be dedicated to the piston movement device.
One of the first such inventions was U.S. Pat. No. 631,078 to King. The King patent shows a piston attached to a string in a pulley orientation. As the string is pulled the piston is forced to rise, thus dispensing a material stored above the piston. Another early technology for moving materials stored within a container is exemplified by U.S. Pat. No. 1,810,249 to Koehler and U.S. Pat. No. 2,402,072 to Nehrke. Both patents show materials moved by the relative movement of a flexible track attached to the bottom supports of the stored materials. As the tracks are moved downwardly on the outside of the container, the track on the inside of the container is forced upwardly, transporting the attached material supports. A similar technology is shown in U.S. Pat. No. 3,229,865 to Heisler et al. In the Heisler patent a flexible track is stored on the outside of a container, as the track is forced into the container, the piston, which is attached to the end of the track, is forced upward.
A more modern technology used to move pistons within containers, uses a segmented flexible track member to push the bottom of the piston. Such devices are exemplified by U.S. Pat. No. 4,318,499 to Hamilton. In the Hamilton patent the segmented track is stored in a serpentine orientation, minimizing the space needed within the container. The segmented track is propelled forward by the mechanical engagement of one segment at a time, transferring the applied mechanical force directly to the pistons base. The present invention also uses a flexible segmented track that is propelled forward by mechanically engaging one segment of the track at a time. However, in the present invention, the track is either preformed into segments that independently support one another, or the track is formed in a flat orientation that is transformed into a usable form just prior to the tracks engagement with a mechanical drive means. Both embodiments minimize the space within a container that must be dedicated to the storage of track. And both embodiments eliminate the need for track supporting, because the orientation of the present invention tracks prohibit buckling or bending of the tracks when the tracks are under compression. Consequently, the track can be stored in many bent orientations when not used, but once put to use in advancing the piston, the tracks orientation makes the track become rigid under the compression force of the resisting piston. This minimizes the space needed to store the track when not being used, and eliminates the need of a track support when the track is in use.
Thus, although prior art does show the use of segmented track driven pistons, prior art does not teach nor suggest the technology described by the present invention in the attached specifications or appended claims.